Rights statement: This is the author’s version of a work that was accepted for publication in Composite Structures. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Composite Structures, 223, 2019 DOI: 10.1016/j.compstruct.2019.110995
Accepted author manuscript, 1.85 MB, PDF document
Available under license: CC BY-NC-ND
Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Article number | 110995 |
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<mark>Journal publication date</mark> | 1/09/2019 |
<mark>Journal</mark> | Composite Structures |
Volume | 223 |
Publication Status | Published |
Early online date | 16/05/19 |
<mark>Original language</mark> | English |
Cast-in-situ concrete-filled steel tube (CFST) structures are inevitably subjected to preload that are developed in the steel tube during the construction process. These preloads may have detrimental effects on the overall performance of a CFST component, such as a CFST column, especially when the column is subjected to elevated temperature. However, existing design methods of CFST exclude the impacts of preload in fire resistance design. In this paper, a three-dimensional finite element model for predicting fire resistance of CFST with preload is developed and validated by experimental tests. The model is then used to predict fire resistance time of CFST columns with different slenderness, load and preload ratios. The results show that preload of the steel tube have little influence on the fire resistance of short CFST columns, while the influence of preload on the fire resistance can be significant when the slenderness ratio is greater. Further increase of the slenderness ratio exceeding a certain range, however, reduces the effect of preload. It can be generally concluded that fire resistance of slender CFST columns decreases with increase of preload ratios and the effect of preload on fire resistance of CFST columns is more prominent when the load ratio is greater. In addition, formulas for calculating fire resistance of cast-in-situ concrete-filled steel tubes (CFST) with preload are proposed. This paper is a companion paper of Yu et al. (submitted for publication).